nRF52 NRF_RADIO-TXPOWER possible range?

[CurtisHx]

What is the minimum and max value that the NRF_RADIO->TXPOWER register can get set to? The datasheet it takes a signed 8 bit for the setting, but what happens if you set it to 10? Does it get clipped at 4?

What about the minimum TX power? Is -128 a valid TX power? How low can it actually go?

[RichieJH]

Per SDK 11 documentation it states the following * @param[in] tx_power Radio transmit power in dBm (accepted values are -40, -30, -20, -16, -12, -8, -4, 0, and 4 dBm).

If it's not one of those values then you get a non-nil return (i.e. error for invalid parameter) which you can then handle but it just continues using the previous value I believe.